1. Field of the Invention
The present invention relates generally to devices and methods for simultaneously treating different medical conditions of a patient, and more particularly, to implantable meshes having conductive elements incorporated therein, that may be used in conjunction with neurostimulation devices or other devices for electrically stimulating selected body parts.
2. Background Discussion
Implantable surgical meshes have been widely used for a variety of different surgical procedures such as hernia repair, pelvic floor repair, urethral slings for treating incontinence, and many others. In hernia repair, meshes are placed surgically to repair the protrusion or defect. Various mesh materials and configurations have been proposed to reinforce the abdominal wall and to close abdominal wall defects by different methods well known in the art. In pelvic floor repair, mesh is used to repair the prolapse of organs within the pelvic cavity. These conditions typically involve organs, namely the bladder, bowel and uterus, that are normally supported by the pelvic floor, but have herniated or protruded into the vagina. The most common cause of pelvic floor prolapse is vaginal childbirth.
Implantable meshes have also been used to treat incontinence. The relatively thin piece of mesh, known as a “urethral sling”, is passed using a needle, without open surgery, via a suitable path that leaves the sling positioned beneath the urethra so that it provides support to the urethra under circumstances where pressure is being exerted on the urethra from the abdomen (i.e., during coughing). One such method is described in detail in U.S. Pat. No. 5,899,909, which is incorporated herein by reference in its entirety. According to this method, the tape or sling is implanted by passing an elongated, curved needle that is attached to one end of the tape through an incision in the vaginal wall, to one lateral side of the urethra, through the pelvic tissue behind the pelvic bone, and exiting out through an incision made in the abdominal wall. The procedure is then repeated passing the other end of the tape on the other lateral side of the urethra. After the tape is properly positioned, the free ends that extend outside of the abdominal wall are trimmed. Over time, fibroblasts grow into the tape to anchor the tape in the surrounding tissue. Thus, the tape is left as an implant in the body to form an artificial ligament supporting the urethra.
Sub-urethral slings have also been placed by a different approach, wherein a needle is passed first through the abdominal wall, along the same path as described above, and eventually exiting through the vaginal incision. The tape is then coupled to the needle in some manner, and pulled back through the body from the vaginal incision and out through the abdominal incision. The chosen approach, vaginal or abdominal, will often depend on the preferences of the surgeon. Yet another approach for implanting a sub-urethral sling has been recently developed, wherein the sling is placed via a pathway extending from a vaginal incision out through the obturator foramen. In still another known method, the sling is similarly placed beneath the urethra, yet is anchored within the pelvic cavity in some fashion (bone or tissue anchors) rather than extending out of the body through an incision in the abdomen or obturator foramen.
As indicated above, urethral slings, of whatever type and placed by whatever means, are used to treat stress incontinence. While stress incontinence is typically a result of an anatomical defect, another form of incontinence, urge incontinence, appears to be neurologically based and generally revealed as detrusor muscle instability or “bladder spasms.” As such it is usually not conducive to surgical correction. In some cases, women can have both stress and urge incontinence, a condition known as mixed incontinence. In many of these cases, the woman is treated for stress incontinence only to be disappointed when incontinence due to bladder spasms does not resolve itself. The urge component of mixed incontinence would then need to be treated on its own, involving additional intervention. Urge incontinence may or may not result in urine leakage, but both conditions otherwise have similar symptoms and similar forms of treatment, which generally include a combination of behavioral modification (learned strategies for reducing the urge sensation, scheduled voiding, avoidance of bladder-stimulating substances such as caffeine, and pelvic muscle exercises, with or without biofeedback) and drug therapy (typically anticholinergeic agents such as oxybutynin or tolterodine). These treatments require life-long therapy. Unfortunately, behavioral modification requires continuous effort to maintain results and the available drugs have significant side effects for many patients, causing 80% to discontinue therapy within a year. The alternative therapy is to modify lifestyle to accommodate the condition—frequent urination to avoid “accidents” and wearing protective pads or undergarments, depending on the severity of the condition.
Another approach for treating urge incontinence is the stimulation of nerves that innervate the pelvis or lower urinary tract. The sacral spinal nerve roots separate in pairs to exit laterally through the nerve root foramina. The main destinations for these roots are the sacral plexus. Nerves from this plexus provide the motor and sensory innervation of the lower limbs and pelvic organs. Specifically, the sacral plexus splits into five sacral nerve pairs, sacral spinal nerves S1 to S5. These nerves supply the thighs and lower parts of the legs, the feet, most of the external genital organs, and the area around the anus. The pudendal nerve is the largest branch of the pudendal plexus and is composed of somatosensory, somatomotor and autonomic elements derived from the anterior primary divisions of the second, third and fourth sacral nerves. The pudendal nerve affects the function of the bladder, urethral sphincter and genitals. Lower branches of the pudendal nerve contribute to peristalsis of the colon and anal sphincter contraction force. The pudendal nerve is closer to the bladder, and its stimulation innervates the bladder, thus eliminating or lessening its contractions. At least one known commercial device sold by Medtronic, Inc. of Minneapolis, Minn. stimulates the sacral nerve through a needle extended into the sacral nerve bundle. This device, however, supplies a continuous signal to provide constant stimulation of the nerve. Various drawbacks of this device include its invasive nature, and unwanted stimulation effects on other areas of the body, since the sacral nerve as a whole is being stimulated and multiple other areas of the body are innervated by such stimulation (i.e., resulting in leg twitches or the like).
A company called Advanced Bionics has an implantable stimulation device that targets the pudendal nerve specifically rather than the sacral nerve. This device is implanted in the vicinity of the pudendal nerve, but also is invasive and supplies a constant signal as described above and therefore, has the same drawbacks.
In addition to incontinence, women can suffer from other diseases as well, often simultaneously with incontinence. Interstitial cystitis is a chronic bladder condition involving an inflamed or irritated bladder wall. Patients with this condition may experience mild discomfort, pressure, tenderness, or intense pain in the bladder and surrounding pelvic area. Other symptoms may include an urgent need to urinate (urgency), frequent need to urinate (frequency), or a combination of these symptoms. The inflammation can lead to scarring and stiffening of the bladder, less bladder capacity (the bladder is able to hold less urine), and pinpoint bleeding in the bladder lining. In rare cases, ulcers form in the bladder lining. Of the more than 700,000 Americans estimated to have interstitial cystitis, about 90 percent are women.
Treatments for interstitial cystitis include oral medicines, such as aspirin, ibuprofen, other painkillers, antidepressants and antihistamines. Another treatment is bladder instillation (a bladder wash or bath) in which the bladder is filled with a solution that is held for varying periods of time before being emptied. These treatments require life-long therapy. Sacral nerve stimulation implants are also used for the treatment of interstitial cystitis, but, as stated previously, its invasive nature and unwanted stimulation effects on other areas of the body make this treatment undesirable. Surgery, considered a treatment of last resort, does not necessarily improve symptoms.
Other diseases that may occur simultaneously with urinary incontinence include fecal and anal incontinence. Fecal incontinence is the inability to control the bowels, and can have several causes with constipation being the most common. Fecal incontinence can also be caused by injury to one or both of the ring-like muscles at the end of the rectum called the anal internal and/or external sphincters. In women, the damage often happens when giving birth. Hemorrhoid surgery can damage the sphincters as well. Fecal incontinence can also be caused by damage to the nerves that control the anal sphincters or to the nerves that sense stool in the rectum. Nerve damage can also be caused by childbirth, a long-term habit of straining to pass stool, stroke, and diseases that affect the nerves, such as diabetes and multiple sclerosis. In addition, rectal surgery, radiation treatment, and inflammatory bowel disease can cause scarring that makes the walls of the rectum stiff and less elastic. Abnormalities of the pelvic floor, which is typically caused by childbirth, can also lead to fecal incontinence. Examples of some abnormalities are decreased perception of rectal sensation, decreased anal canal pressures, decreased squeeze pressure of the anal canal, impaired anal sensation, a dropping down of the rectum (rectal prolapse), protrusion of the rectum through the vagina (rectocele), and/or generalized weakness and sagging of the pelvic floor. Treatment depends on the cause and severity of fecal incontinence, and may include dietary changes, medication, bowel training, or surgery. A last resort is a colostomy, which is the surgical creation of an opening between the large intestine and the abdominal wall. More than one treatment may be necessary for successful control since continence is a complicated chain of events.
One type of treatment typically cannot be used to treat the different conditions described above, and, as indicated above, many of the known treatments are invasive or have other negative side effects. Accordingly, what is needed is an improved device and method for simultaneously treating different diseases or conditions.